The present invention relates to an anti-freezing device for use in water supply conduits such as public and household water supplies, and more particularly to an anti-freezing device for such use to prevent the water from being frozen during conveyance without stopping the flow of water.
There have been used a variety of anti-freezing devices, and one example is disclosed in Japanese Utility Model Publication (unexamined) No. 58-129964. This prior art device is adapted for attachment to a water conduit at a place where it is particularly desired to prevent the freezing of water. The device comprises a cylindrical chamber and a working chamber, wherein the cylindrical chamber includes a piston, and a valve secured to the top end of the piston by means of a connecting rod so that the valve comes into contact with the inlet of the cylindrical chamber under the action of the spring. In addition, the device includes several water paths connecting between the working chamber and a part on the conduit where the anti-freezing is required, and a discharge path extending from the working chamber to discharge the water therein outside. When the atmospheric temperature lowers to the freezing-point, the water in the water paths is first frozen thereby to close the cylindrical chamber, and then the water in the working chamber is frozen, thereby causing the volume of water to expand. The volumetric expansion pushes back the piston against the spring, thereby separating the valve from the inlet of the cylindrical chamber. In this way the water in the conduit is introduced into the discharge path through which it is discharged outside. The flowing through the conduit prevents the water from being frozen therein.
This known device is constructed without considering the thermal relationship between the discharging water flowing through the discharge path and the water (or ice) in the working chamber. As a result, once the valve is opened as the water in the working chamber freezes, it is kept open thereby to continue to discharge the water until the ice in the working chamber starts to melt as the atmospheric temperature rises up. Particularly in cold seasons the water discharge lasts for a long time because the rising of atmospheric temperature is slow. This is indeed a waste of water, and is uneconomical.
An object of the present invention is to provide an anti-freezing device adapted for use in water conduits, the device preventing the freezing of water without stopping the flow of it.
More specifically, the anti-freezing device of the present invention opens in response to a drop in the atmospheric temperature, thereby discharging the water in the water supply conduit outside through the device, and closes in response to the temperature of the water almost independently of a rise in the atmospheric temperature. Thus the waste of water is avoided.